Mechanics

HARD START/ROUGH IDLE/ WONT REV UP

1993 Lincoln Mark VIII

Engine Performance problem
1993 Lincoln Mark VIII V8 Front Wheel Drive Automatic

engine is very hard to start. It starts and dies. When it does run it is very rough and will not rev up. I managed to get it to run long enough to plumb in a vacuum gauge. Manifold vacuum is less than 10" and drops to zero and engine quits. I suspect a stuck egr or faulty intake gaskets. Have you any other suggestions? Thanks for your time and help
Avatar
Larry's heavy duty
May 8, 2010.



If the check engine light is on read the codes, this is always the first step, here's how, Post all codes found, and I will tell you what's next.
READING CODES
KOEO & KOER SELF-TEST Codes
PCM outputs codes one digit at a time. Record codes in order received. These codes indicate current
faults in system and should be serviced in order of appearance. Use SERVICE CODE-TO-TEST
MENUS to find correct CIRCUIT TEST.
If using VOM, pay careful attention to length of pauses in order to read codes correctly. A 1/2-second
pause occurs between number of sweeps in a digit. A 2-second pause occurs between digits in a code.
A 4-second pause occurs between each code. KOEO codes are separated from Continuous Memory
codes by a 6-second delay, a 1/2-second sweep (separator) and another 6-second delay. See Fig. 1.
If using MIL/CHECK ENGINE light, service codes are displayed as flashes. On Continental, message
center may be used to display codes. See Fig. 2.
Scan tester, if used, will count pulses and display them as a digital code. STAR Series Tester will add
a zero (0) to single-digit Separator Code (10) and Dynamic Response Code (10). Dynamic Response
Code is displayed in KOER SELF-TEST. See Fig. 1.
Separator Pulse
Single 1/2-second separator pulse is issued 6-9 seconds after last KOEO code. Continuous Memory
Codes (soft faults) are then displayed 6-9 seconds after 1/2-second separator pulse. Some digital test
equipment may display separator code as "10" instead of "1".
Pass Codes
A Code 11 or 111 indicates no service codes were recorded in that portion of test; system passes that
portion of test. If Code 11 or 111 is not retrieved in KOEO SELF-TEST, codes retrieved during
KOER SELF-TEST may not be valid. Code 11 or 111 (pass code) must be obtained in KOEO SELFTEST.
A Code 11-1-11or 111-1-111 output during KOEO SELF-TEST indicates no KOEO code or
Continuous Memory Code was recorded.
Continuous Memory Codes
These codes result from information stored by PCM during continuous self-test monitoring. Codes are
displayed after separator pulse code in KOEO SELF-TEST. Use these codes for diagnosis only when
KOEO SELF-TEST and KOER SELF-TEST result in Code 11 or 111 (pass code) and all steps under
QUICK TEST are successfully completed. (A few codes are exceptions which may be checked after
KOEO codes have been repaired). These codes indicate faults recorded within last 40 engine starts
(80 engine starts on some models). Fault may or may not be currently present. See SERVICE CODETO-
TEST MENUS.
Fast Codes
At start of KOEO SELF-TEST and after Wide Open Throttle (WOT) request in KOER SELF-TEST,
PCM outputs short bursts of information, known as FAST CODES, which were used by manufacturer
during assembly. With most equipment, these code bursts are not visible; an entire code sequence
lasts less than 1/2 second. If this fluctuation is visible on test equipment, ignore it.
Fig. 2: Message Center Self-Test (Continental)
Courtesy of FORD MOTOR CO.


http://www.2carpros.com/forum/automotive_pictures/62217_23_1.jpg



http://www.2carpros.com/forum/automotive_pictures/62217_Self_Test_Hook_UP_1.jpg



http://www.2carpros.com/forum/automotive_pictures/62217_Flow_Chart_1.jpg



http://www.2carpros.com/forum/automotive_pictures/62217_Contintal_Code_Reading_OBD_I_1.jpg


Merlin2021
May 11, 2010.
The codes according to the service eng lite flash are 1 flash pause 1 flash; 3 flashes pause 5 flashes; 3 flashes pause9 flashes. According to my chart codes 11; 35 and 39. The eng will not start. Fuel pressure koeo is 35/40psi. If I pour a drop of gas into the throttle body the eng will fire. Ckp shows a pulse on ac voltage. The injectors are receiving a pulse/ checked with a noid lite. I do not know how to check the ignition timing and as this is a low mileage vehicle I don't think there is a valve timing problem

Tiny
Larry's heavy duty
May 12, 2010.
35. EGR Valve Position/EGR Pressure Feedback (above maximum voltage), or rpm too low for EGR test (2.3L OHC & 3.8L CFI)
39. AXOD Converter Bypass Clutch not Applying Properly
You can get it to start by putting gas into the throttle, this means there is a fuel delivery problem, look in the trunk for the inertial switch, make sure the red button is pressed down.
3.8 engine?

Merlin2021
May 13, 2010.
I think the inertia switch is ok. I have 35psi fuel pressure koeo. As I already stated I have checked injector pulse with a noid lite and the injectors are receiving a pulse from the ecm. Do I have enough fuel pressure? I have have checked the fuel delivery with the supply disconnected and when the key is turned on the pump pumps for a fews seconds and there seems to be enough fuel. The intake manifold runners do not seem to be stuck open or hanging up. Is it possible I have a major vacuum leak and by pouring fuel into the throttle the mixture is rich enough to fire?

Tiny
Larry's heavy duty
May 13, 2010.
KOEO 35-40 psi is dead on, Did you check the EGR for sticking open. Check for carbon under the valve and jamming the pintle open a bit. This would be a major vacuum leak and cause a no start even with good fuel pressure and spark. The other thing is at the firewall side of the motor, there is a wiring harness that runs back there, wiggle it and see if anything happens, have seen a few that needed to have the harness repaired or replaced.

Merlin2021
May 13, 2010.
I asked about what would could cause hard and no start/ rough idle and no rpm. I appreciate your suggestions. The problem was a plugged exhaust system. The ls primary cat had broken up and plugged the system. I disconnected the exhaust and the thing fired right up.

Tiny
Larry's heavy duty
May 19, 2010.